Remove Valgrind suppression for http://crbug.com/288801

BUG=288801

Review URL: https://codereview.chromium.org/24564002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226274 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226274